From the given information, we know that the sum of the interest must be equal to the total annual interest of $15,000. So, we can write
where x denotes the amount of money at 10% and (175000 -x) the amount of money at 8%. Then, our last equation is equivalent to
Then, by subtracting 14000 to both sides, we have
and by collecting the terms on the left hand sides, we have
Now, by dividing both sides by 0.02, we obtain
Then, $95,000 is the amount paid off at 10%.
Now, by substituting this result into (175000 -x), which corresponds to the amount paid off at 8%, we get
Therefore, the answer is: $95,000 amount paid off at 10% and $80,000 amount paid off at 8%